1. Field of the Invention
The present invention relates generally to nail guns and more particularly, to a nail gun capable of preventing its trigger from being pulled in a nail-empty condition where there isn't any nail in the nail magazine and the muzzle of the nail gun.
2. Description of the Related Art
When people use nail guns, they usually need to shoot nails continuously. Therefore, when there is no nail in a nail magazine and a muzzle of a nail gun, people may still pull a trigger of the nail gun for one time, or even for several more times in order to confirm that there is indeed no nail in the nail gun. However, aforesaid habitual action may damage some firing elements of the nail gun so as to decrease the lifetime of the nail gun. As a result, some enterprises start to design nail guns which can prevent their triggers from being pulled in a nail-empty condition.
For example, U.S. Pat. No. 6,908,021 disclosed a nail gun having a structure for preventing the nail gun from being fired with no nail therein, which comprises a rotatable shaft disposed on one side of a nail magazine of the nail gun, a driven piece attached to a front end of the rotatable shaft, and a locking piece extending from a rear end of the rotatable shaft toward a trigger of the nail gun. The driven piece penetrates through a side wall of the nail magazine and is stopped against a nail in the nail magazine in normal conditions. After the nails in the nail magazine are shot to a certain extent, there will be no nail to be abutted by the driven piece. At this moment, the driven piece will move inward the nail magazine and make the rotatable shaft rotate about an axis parallel to the marching direction of the nails so as to make the locking piece move toward the trigger. As a result, the locking piece will lock the trigger so that the nail gun can't be fired any more. At this moment, however, there is still at least one nail in a muzzle of the nail gun, which can be shot only if the user turns the rotatable shaft manually to move the locking piece away from the trigger, and that is very inconvenient.
Besides, in the above-mentioned design, the aforesaid locking piece is stopped right behind the trigger to prohibit the trigger from movement when the trigger is pulled; therefore, the locking effect thereof may decrease when the trigger is a little bit deformed due to a long time or improper use. As a result, the locking piece may loosen while receiving the vibration of firing, or even totally lose its function of preventing the trigger from being pulled in a nail-empty condition.
Furthermore, Taiwan Patent No. M369230 disclosed a nail gun having a safety sliding shaft which can be moved by a nail pushing member in the nail magazine to prevent the nail gun from being fired with no nail therein. Although the nail gun can solve above-mentioned problem, the structure of the nail gun is complicated to need improvement.